JSFiddle - React, Tailwind, and code Playground

HTML

<div class="triangle"></div>

CSS

.triangle {
    color: crimson;
    width: 0;
    height: 0;
    margin-top: 30%;
    border-top: 100px solid crimson;
    border-left: 50vw solid transparent;
    border-right: 50vw solid transparent;
}